Despite proved efficacy in reducing pain for osteoarthritis patients, Kolon Life Science’s Invossa has been facing criticism that it is “a painkiller costing several million won.”

However, the company said it was confident to make Invossa “Korea’s first global blockbuster drug” through global phase-3 clinical trials.

In July, the gene therapy Invossa obtained the 29th local new drug status from the Ministry of Food and Drug Safety (MFDS) for the indication in “alleviating symptoms (reducing pain and improving joint functions),” not in “improving cartilage structure.”

Considering the long development period of 19 years and its high cost of several million won per shot, the drug’s clinical efficacy fell short of expectations, critics said.

Such negative sentiment affected the company’s stock prices to go down. On the announcement of the approval for Invossa, shares of Kolon Life Science plunged by 15.8 percent on July 12 from 174,900 won ($160) the previous day.

However, Kolon Life Science boldly announced plans to prove Invossa’s efficacy on improving cartilage structure through global phase-3 clinical trials and to expand indications from osteoarthritis on hands and hip joints to musculoskeletal diseases on intervertebral disc, rheumatism, and semilunar cusp. The company emphasized that improvement of cartilage structure was not a “primary endpoint” of the local study when it submitted local clinical trial data to the health authorities for approval.

Lee Woo-sok, CEO of Kolon Life Science

Lee Woo-sok, CEO of Kolon Life Science, explained about the company’s stance as a keynote speaker at the “2017 Biotech Industry Performance Sharing Forum” at the L Tower in Seoul, Tuesday. The event was hosted by Korea Evaluation Institute of Industrial Technology and Korea Biotechnology Industry Organization.

“In the local clinical trial, improvement of (cartilage) structure was not a primary endpoint. The company didn’t expect it from the study, either,” Lee said.

“We have confirmed the drug’s inclination to efficacy on the improvement of cartilage structure. But the local phase-3 clinical trial had only 159 patients, which made it difficult to produce statistically meaningful results.”

Lee said Invossa’s efficacy on improvement in cartilage structure will be proved through a phase-3 clinical trial on more than 1,000 patients in the U.S.

He went on to say that the local phase-3 trial had a one-year observation but the U.S. Food and Drug Administration requires at least two years of observation to prove cartilage structural improvement.

“Global phase-3 clinical trials with two-year observation will be able to offer statistical evidence for cartilage structural improvement,” Lee said.

Through the U.S. trial, Invossa aims to be approved by the FDA as disease-modifying osteoarthritis drug (DMOAD).

To be recognized as a fundamental treatment, Invossa should prove that its long-lasting effectiveness for pain reduction and joint function improvement, as well as improvement in cartilage structure.

Unlike the local clinical trial which was on patients with K&L Grade 3, the second most severe osteoarthritis under the Grade 1 to 4 Kellgren & Lawrence Classification, the global phase-3 clinical trial has been designed to include K&L Grade 2 patients. Such inclusion will make the company easier to prove Invossa’s efficacy on improvement in cartilage structure of patients with less severity, Lee said.

He also expressed regret over the MFDS’ mentioning of cartilage structure improvement in its announcement of approval for Invossa. As cartilage structure improvement was not included in the local clinical trial’s design, it is more accurate to say the company has not conducted a related clinical trial for such efficacy than to say the drug has failed to prove the efficacy, Lee said.

Announcing the approval for Invossa, the MFDS said in a press release that “the drug did not show a difference from the control group in efficacy on improvement in cartilage structure in MRI (magnetic resonance imaging).”

“I have faith in Invossa’s strong potential to become the first fundamental treatment for osteoarthritis. While Invossa is Korea’s 29th novel drug, it will become the first global blockbuster drug from Korea,” Lee said.

“Not only in Japan where Invossa had been licensed out, we will seek partnerships in many other countries,” he added.